No Brakes

[TjBlueRusty]

This is a 1975 C-10 1/2 ton that sat for about 10 years. The easy part was getting it running the hard part seems to be getting it stopped. Heres the story. The master cylinder was empty of brake fluid. I added some on its initial drive but no brakes. I drove it slowly on some rural roads for a few miles. The right front caliper froze locking the wheel. I next relpaced both front calipers and then tried to bleed them. Started with the passerger side and after about 5 attempts I seen fluid leaking from a line going to the rear. It was rusted out. I replaced it and started the bleeding processes again. I started with the right rear but I twisted off the bleeder value. Went over to the drivers side but was unable to get any fluid. I moved to the front and got no fluid. I then tested the master cylinder and fluid shot out when I cracked open a line.
I then tried pumping fluid up from the bleeder valves. I started at the rear but it did not take much fluid and the MC reservior level never changed. Tried the right front and it took a descent amount of fluid but the MC level never changed. The left front took little fluid and the MC level never changed. Not sure what to do next. Could the Combination Valve be my problem? What's the easiest way to remove it? Looks like the radiator has to come out first. Any other suggestions?

This truck will only be driven in pastures/fields and some rural roads. If I can get just a couple of brakes working it will do.
Thanks.

[tecky11]

did you check the brake booster(if equipped)?

[old Rusty C10]

i dont care whether youre driving the truck in fields or not the correct thing to do is to have four brakes working on this thing properly.... you can kill yourself or someone else in a pasture as quick as you can on a road with faulty brakes
that being said
you should have bled the master as if it was being installed fresh . there was no fluid in the masterso that makes me wonder if the seals on that are any good to begin with.
at this point you need to begin checking all parts of the brakes....
start by bleeding the master going down to the proportioning valve then to the rubber lines to the front and the one on the rear axel
make sure all your steel lines are good then make sure that your wheel cylinders are good
You should also make sure that no fluid is leaking from the master into the power booster if equipped

[TjBlueRusty]

Thanks for the advice and concerns. The master cylinder is bled and works fine. I also had fluid squirting out of the rusted line by the rear end before replacing it.
I'm wondering if the rear rubber line, that connects to the newly replaced line, is plugged and the combination valve has the front blocked off. My next trip out there I'll disconnect the new line and see if I can push fluid from the rear wheel out to where I've taken the line appart.

I've read some posts about using a C clamp to reset the combination valve but I'm not clear on where and how it works. It's in a bad place and I didn't get a good look at it and since the truck is 150 miles away I want to have a good idea of what I can and can't do. Does anyone have a picture of it being done or a link to a thread showing it?

Thanks.